Overview of the static keyword
About static keyword, which can be used to modify the member variables and member methods , modified members belong to the class, rather than just part of an object. In other words, since belong to the class, you can not rely create objects called.
1.static static keyword
2.static can be used to modify the member variables and member methods
static modification member variables
When the static modification member variable when the variable is called a class variable . Each object class share the same class variable values. Operate on class variables without any object can change the value of such variables, but you can not create objects of that class in the.
static data type variable name; e.g. static String name;
2, features:
Modified static member variables will become static variables , static variables not only belong to just one object, but belong to the class, so static variables are shared by all objects of that class, which means that all objects of that class using the same data
3, static member variables of access:
Object name. Static member variable name
The class name. Static member variable names recommended
Static method
static modification member methods
1. Format:
In fact, the definition of the method when, in front of the return type of the static keyword to add value
Static modifier return type method name (parameter list) {
The method body
}
2. Static member method access:
The object name static method name (arguments);
Static class name method name (arguments); Recommended
3. Note:
Non-static method can directly access both static and non-static member
Static method can directly access only static members, can not directly access non-static member
Static methods can not appear in this
Static members: contains static member variables and static member methods
Non-static member: non-static member variables and non-static member methods
static (Static) block
static can be used to modify the code block -> static code block
1. Format:
static { code block}
2 positions: an outer class methods
3. Execution:
With the loaded class is executed and performs a priority for performing the method of the main methods and constructors.
For the first time using the class will load the class, and only loaded once